Had a rather annoying (and very stupid) coworker many years ago when I was a poor college student working nights at a grocery store.
Sometime after the holidays, we had a few cases of instant jello powder we had to throw out because it had expired. It was a cold night, so a coworker and I sealed the gaps in the annoying coworkers tailgate and pickup bed with pallet wrap and trash bags, pulled out the long garden hose, and filled the bed half way full of water. Then mixed in the jello powder with a mop handle.
Wish I had a photo of the guys face when he clocked out at the end of shift and found his early 90's ford ranger with 50 gallons of jello pudding in the bed.
At one time I convinced the stupid coworker I saw imaginary cats and I'd bark at them like a dog. For weeks he thought it was real and I couldn't help it.
Same store, different employee. Frozen food clerk was a regular prankster. One evening he took my jacket I used when working in the walk in coolers in the back, wrapped it into a tiny ball with pallet wrap, and tossed it into the "attic" over the big coolers. Took me weeks to find it. He'd also found another coworker's lunchbox while they were out on vacation. He put an open tin of sardines in it and left it in a warm place all week.
I and the other pranked coworker decided that revenge would be cold and painful. We learned he'd had a years-long crush on a local young woman. We managed to convince the lady to write a short note to the prankster, saying she was interested in meeting up with him for dinner and drinks in town. We set up a (fake) date with the prankster and the woman of his dreams.
He shows up to the place on time, dressed up, and gets a table for two. I and the other coworker are sitting in the parking lot, laughing our backsides off. He waits. And waits. And we watch. 1.5 hours later, the place closes, and he's ushered out by a waitress, his girl never showed up. Dude was crying as he got into his car. Blew the horn and waved at him as we slowly drove by. Don't screw with us.
In high school I was fond of picking up a few extra milk cartons and taking them home. Let them sit in the sun for a few weeks. Then bring them back, unopened, and get to the lunch room early and set them out on the table. Was funny watching people open their "free" milk, only to tip the chair over backwards when the smell hit them.
Connecting a jumper wire from the brake light fuse to the horn fuse can be fun. Someone's horn blows each time they hit the brakes.
Meanest one I've ever seen (I didn't do it, but I was a witness) Blend up a can of tuna or sardines really fine with a blender, and then use a turkey injector needle to inject the slurry into the upholstery in someone's car. The smell NEVER goes away. And good luck selling it.
